All contracts or agreements of redevelopment commissions heretofore entered into with the federal government or its agencies, and with municipalities or others relating to financial assistance for redevelopment projects in which it was required that loans or advances shall bear an interest rate in excess of six per centum (6%) per annum, or in which a municipality or others had agreed to pay funds equal to the interest in excess of six per centum (6%) per annum are hereby validated, ratified, confirmed, approved and declared legal with respect to the payment of interest in excess of six per centum (6%), and all things done or performed in reference thereto. The redevelopment commissions are hereby authorized to assume the full obligation of the municipalities under the contracts or agreements with reference to interest in excess of six per centum (6%), and to reimburse any municipality which has made any interest payment under such contracts or agreements. (1971, c. 87, s. 4; 1973, c. 426, s. 75.)